Pumping and cooling system



p 1970 w. F. BOYLETT ET AL 3,526,102

PUMPING AND COOLING SYSTEM Filed Aug. 21, 1968 5 Sheets-Sheet l A nvenloM L L) ,W

Sept. 1, 1970 w. F. BOYLETT ET AL 3,526,102

PUMPING AND COOLING SYSTEM I Filed Aug. 21. 1968 5 Sheets-Sheet 2 Sept.1, 1970 w. F. BOYLETT ET AL 3,526,102

PUMPING AND COOLING SYSTEM Filed Aug. 21, 1968 5 Sheets-Sheet 5 Se t. 1,1970 w. F. BOYLETT ET AL 3,526,102

PUMPING AND COOLING SYSTEM 5 SheetsSheet 4 Filed Aug. 21, 1968 AInventors Sept. 1, 1970 w. F. BOYLETT ET AL 3,526,102

PUMPING AND COOLING SYSTEM Filed. Aug. 21. 1968 s Sheets-Sheet 5 UnitedStates Patent Office 3,526,102 Patented Sept. 1, 1970 3,526,102 PUMPINGAND COOLING SYSTEM William F. Boylett, Ormskirk, Joseph William Hill,Saint Helens, Tom B. Leamon, Ormskirk, and George Shaw, Bickerstaif,England, assignors to Pilkington Brothers Limited, Liverpool, England, acorporation of Great Britain Filed Aug. 21, 1968, Ser. No. 754,283Claims priority, application Great Britain, Aug. 25, 1967, 39,195/ 67Int. Cl. F25d 23/12; B67d 5/62 US. Cl. 62-259 ABSTRACT OF THE DISCLOSUREA pumping and cooling system for a protective suit comprises a coolantcircuit including passages in the suit and a flow passage in heatexchange with an evaporating refrigerator; and a reciprocating pump inthe circuit is operated by pressure fluid from the refrigerant throughvalve means having two settings corresponding to the two strokes of thepump and operated cyclically by changeover means.

BACKGROUND OF THE INVENTION Field of the invention This inventionrelates to pumping and cooling systems for circulating coolant in aclosed fluid circuit, including, for example, coolant channels inprotective clothing.

Description of the prior art A well known form of protective clothingfor wear by personnel who are required to work in uncomfortably hotsurroundings or in areas exposed to intense heat radiation, has a liningprovided with channels through which a coolant, usually a liquid, iscirculated by an external pump. Associated with the pump is arefrigerating unit for extracting heat from the coolant. Usually thepump and refrigerating unit are provided in a static installationlocated outside the high temperature working area, but this isunsatisfactory where personnel need to have a high degree of mobility asit is necessary to link the protective clothing with the staticinstallation by fluid supply and return lines.

One object of the present invention is to provide a pumping and coolingsystem which may be compact and of lightweight construction, so thatwhen it is employed to circulate coolant in protective clothing asdescribed above it may be carried by the wearer of the protectiveclothing, thereby freeing the apparatus of any connection to an externalstatic installation.

SUMMARY A pumping and cooling system according to the present inventioncomprises a sealable vessel arranged in heatexchange relationship with acoolant flow passage which is adapted to form part of a coolant circuit,said vessel being adapted to contain an evaporating refrigerant whichreleases pressure fluid upon absorption of heat, a fluidpressure-actuated reciprocating pump connected in the coolant circuit,and having a control connection to the vessel for supplying pressurefluid to control the pump, valve means in the control connection betweenthe vessel and the pump and having two settings corresponding toinduction and delivery strokes of the pump, and changeover meanseffective to change the setting of the valve means cyclically so thatthe pump effects continuous reciprocation.

The system according to the invention is readily adaptable for portableuse, as for continuous operation of the pump it is necessary only toprovide a suitable heat-absorb- Claims ing medium in the vessel. Such amedium preferably comprises a solidified or liquefied gas exposed to atemperature in excess of its sublimation or boiling temperature. Solidcarbon dioxide is particularly suitable as its sublimation point isbelow normal atmosphere temperature.

In a preferred embodiment the valve means has two fluid outlets and isoperable to supply pressure fluid from the sealable vessel to the twooutlets in turn.

Desirably the changeover means is connected to a movable part of thepump and is effective automatically when the pump is at the end of astroke to change the setting of the valve means so that the pumpcommences the next stroke.

Preferably a change of setting of the valve means is effected by theapplication of fluid pressure controlled by the changeover means, thechangeover means being effective to provide a communication between saidvessel and a fluid inlet associated with said valve means, at whichinlet fluid pressure can be applied to effect a change of setting of thevalve means.

The valve means according to one preferred embodiment of the inventioncomprise a spool valve movable axially in a housing, the changeovermeans being effective to provide selectively a communication betweensaid vessel and a fluid inlet at one end of said housing, and betweensaid vessel and a fluid inlet at the other end of said housing, a changeof setting of the valve means being effected by application of fluidpressure at the fluid inlet at the appropriate end of said housing tomove the spool valve axially.

In an alternative preferred embodiment the valve changeover meanscomprise sealing means mounted for movement with the pump and arrangedto block an exhaust port when the pump is at the end of a stroke, a ductproviding communication between said exhaust port and said vessel, andhaving a control outlet communicating with said duct at which fluidpressure can be applied to effect a change of setting of the valvemeans, whereby when said exhaust port is blocked by the sealing meansfluid pressure is applied at said control outlet to cause a change insetting of the valve means.

In such an embodiment the system may include a first duct having anexhaust outlet and communicating with a control outlet at which fluidpressure can be applied to change the valve means from a first settingto a second setting, and a second duct having an exhaust outlet andcommunicating with a control outlet at which fluid pressure can beapplied to change the valve means from said second setting to said firstsetting, said first and second ducts communicating with said vessel, andwherein the pump has associated therewith respective sealing meanseffective to block the exhaust outlets of said first and second ductswhen the pump is respectively at the end of a pumping stroke and aninduction stroke, so that fluid pressure is applied to the first andsecond control outlets alternately.

The sealable vessel preferably comprises a container for the evaporatingrefrigerant enclosed in a jacket which defines with the container saidcoolant flow passage.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammatic cross-sectionof pumping apparatus in a preferred embodiment of the invention;

FIG. 2 illustrates diagrammatically and partly in section a combinedpumping and cooling system incorporating the apparatus of FIG. 1;

FIGS. 3A and 3B illustrate diagrammatically a combined pumping andcooling system according to an alternative embodiment of the invention,and

FIG. 4 is a diagrammatic cross-section through an alternative form ofpumping apparatus for use in a system according to the invention.

3 DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, afluid-operated pumping apparatus includes a positive displacementdiaphragm pump comprising a pump chamber 11 one wall of which isconstituted by a flexible diaphragm member 12. A fluid inlet 13 andoutlet 14 communicate with the pump chamber 11 by way of respectiveinlet and outlet non-return valves 13', 14'. A pump actuating rod 16 isattached to the centre of the diaphragm member 12, reciprocation of therod 16 flexing the diaphragm member 12 to cause induction of fluidthrough the inlet 13 and expulsion of fluid through outlet 14 on outwardand inward strokes of the rod respectively.

At its end remote from the diaphragm member 12 the actuating rod 16 isconnected to a driving piston 17 which is mounted for sliding movementin a cylinder 18. The piston 17 divides the interior of the cylinder 18into two spaces 19, 20 and provides a seal between said spaces. Thespaces 19, 20 communicate through respective conduits 21, 22 with valvemeans 23 shown generally enclosed in broken lines.

The valve means 23 comprises in this embodiment two respective three-wayrotary valves 24, 25 having respective cylindrical plugs 26, 27 mountedrotatably and fluidtightly in respective cylindrical housings 28, 29.Each plug 26, 27 has a respective L-shaped flow passage 30, 31therethrough and each valve housing 28, 29 is provided with threerespective ports, spaced apart at 90 in the direction of rotation of theplug 26, 27, the central one of which communicates with a respectivesaid conduit 21, 22, and the remaining two of which communicate'respectively with fluid pressure inlet pipes 32, 33 and with exhaustoutlets 34, 35 which vent to atmosphere. The valve plugs 26, 27 arerotatable within their respective housings 28, 29 by means of respectivelever arms 36, 37 between two settings, in the first of which therespective passages 30, 31 provide communication between the respectiveconduits 21, 22 and the respective inlet pipes 32, 33, and in the secondof which the passages 30, 31 provide communication between therespective conduits 21, 22 and the respective exhaust outlets 34, 35.

The valve lever arms 36, 37 are interconnected by a link 38 so that theyare movable in unison, the valves 24, 25 being so arranged that, whenone valve 24 is in its first setting, the other valve 25 is in itssecond setting, and vice-versa. The two fluid inlet pipes 32, 33 areconnected to a common pressure fluid line 40.

The valve means 23 are mounted close to the actuating rod 16, theconnecting link 38 extending parallel to and adjacent the rod 16.Attached to the link 38 at two spaced apart positions are respectivefixed arms 41, 42 which project towards the rod 16 into the path ofmovement of a striker plate 43 aflixed to the rod 16.

Self-sustained operation of the pump 12 may be obtained simply byconnecting the pressure fluid line 40 to a convenient source of fluidunder pressure. Thus, assuming that the valves 24, 25 are disposedinitially in their first and second settings respectively, as shown inFIG. 1, the pressure fluid line 40 will be connected to the space 19through pipe 32, valve passage 30 and conduit 21, while the space 20will be connected to the exhaust outlet 35 through the conduit 22 andthe valve passage 31. The driving piston 17 will accordingly be moved inthe sense of decreasing the volume of space 20, that is, downwardly asviewed in FIG. 1, urging the actuating rod 16 downwardly. The actuatingrod 16 flexes the diaphragm member 12 inwardly, increasing the pressurein the pump chamber and forcing fluid therefrom through the outletnon-return valve 14.

On completion of its pumping stroke the diaphragm member 12 is disposedin the position shown in broken lines at 12', the striker plate 43having engaged the arm 41 and moved it to the position shown in brokenlines at 43'; this movement will have rotated the valve plug 26 and,through the connecting link 38, the valve plug 27, through so that thevalves 24, 25 are now disposed in the second and first settingsrespectively. Pressure fluid is now supplied to the space 20 through thepipe 33, the valve passage 31 and the conduit 22, while the space 19 isexhausted through the conduit 21, the valve passage 30 and the exhaustoutlet 34. Assuming, therefore, that the inlet fluid pressure issufliciently greater than atmospheric to produce a resultant upwardforce on the piston 17 notwithstanding the smaller area of said pistonexposed to the fluid pressure in the space 20, the piston 17 andactuating rod 16 will move in the opposite direction, that is, upwardlyas viewed in FIG. 1. The diaphragm member 12 will be flexed outwardly,effecting an induction stroke of the pump 10 and drawing fluid into thechamber 11 through the inlet non-return valve 13'. On completion of thisinduction stroke the diaphragm member 12 will be in the position shownin broken lines at 12" and the striker plate 43 will have engaged thearm 42 and moved the latter to the position shown in full lines, thestriker plate 43 occupying the position 43". The valves 24, 25 arethereby returned to their first and second settings respectively, andreversal of the direction of movement of the driving piston 16 againtakes place to efiect a further compression stroke of the pump 10.

It will be appreciated that, provided the ratio of the fluid pressureapplied to the line 40 to atmospheric pressure is greater than the ratioof the larger to the smaller area sides of the piston 17 by an amountsuflicient to overcome friction between the piston 17 and the walls ofthe cylinder 18, the pumping apparatus will operate continuously, thepumping speed being dependent on the magnitude of the fluid pressureapplied to the line 40.

The pumping apparatus is incorporated in a combined pumping and coolingsystem as a portable, self-contained cooling unit. Such a unit,employing the pumping apparatus of FIG. 1, is illustrated in FIG. 2, inwhich the pumping apparatus is indicated generally at P and a coolerdevice at C.

Fluid pressure is applied to the inlet pipe 40 of the apparatus P from asealed cylindrical vessel 50 containing solid carbon dioxide. The vessel50 is located coaxially within a cylindrical jacket 51 of largerdiameter, so that a cooling space 52 is defined between the jacket 51and the vessel 50. A respective inlet 53 and outlet 54 for a fluid to becooled communicate with the interior of the jacket 51 at opposite endsthereof.

The fluid coolant, which conveniently is water containing ananti-freezing agent, is circulated in a closed circuit, including thecooling space 52 and an appliance to be cooled, by the pump 10, theoutlet 14 of the pump being connected to the inlet 53 of the jacket 51.The appliance to be cooled comprises in this particular examample aprotective suit 55 provided with coolant channels 56 through which thewater is circulated after passing through the space 52.

The entire cooling and pumping unit is portable, most of the componentsof the pumping apparatus P and the cooler device C being made oflightweight metal such, for example as aluminium. Once charged withsolid carbon dioxide the unit will operate continuously so long as, inpractice, a minimum pressure of carbon dioxide of about 25 p.s.i. ismaintained at the inlet pipe 40. In a typical unit of this type, thevessel 50 was charged with a 7 lb. block of carbon dioxide and thepumping apparatus P maintained a rate of flow of coolant water through asuit 55 of lbs. per hour for some 2 hours, the temperature differencebetween coolant water at the inlet to the unit and that at the outletbeing 5 C. The total weight of this suit, including the initial carbondioxide charge, was 35 lbs.

To facilitate replenishment of the carbon dioxide charge the vessel 50is open at its upper end and provided with a quick-release cover plate58 which seats on a continuous annular flange 59 provided externally ofthe vessel 50 at said open end, an annular sealing gasket 60 beingdisposed between the cover plate 58 and flange 59. The jacket 51 is alsoopen at its upper end and provided at said end with a continuousexternal flange 61. The flange 59 of the vessel 50 is of suflicientradial extent to overlie the flange 61, an annular sealing gasket 62being .disposed between the flanges 59 and 61. A bar 63 extendsdiametrically across the top of the cover plate 58. The bar 63 is formedwith integral C-shaped hooked ends 64 and a clamping screw 65 isthreaded in a bore extending perpendicular to the bar 63 mid-way betweenthe hooked ends 64. When the vessel 50 has been charged with carbondioxide, the cover plate 58 is placed in position and the bar 63 thenmoved across the cover plate in a direction perpendicular to its lengthuntil it extends along a diameter of the plate 58, the hooked ends 64being engaged behind the flange 59. The clamping screw 65 is'thentightened, using a handwheel 65 so that it engages the cover plate 58centrally, clamping both the plate 58 against the flange 59 and theflange 59 against the flange 61, and thereby sealing the cooler deviceC.

Although carbon dioxide is a particularly convenient cooling agent forthe above-described application of the pumping unit, it will beappreciated that, in principle, other cooling agents, comprising eithersolidified or liquefied gases may be used, in conjunction with, ofcourse, a suitable circulating coolant which does not freeze at thetemperature of the cooling agent.

FIG. 3 illustrates an alternative embodiment of the invention, alsodesigned for use as a self-contained portable cooling unit. The coolerdevice C is of the same construction as that of FIG. 2, and, as in theprevious embodiment a coolant is circulated through the cooler device Cand a suit 55 by a diaphragm pump 110.

In FIG. 3, however, the diaphragm pump 110 has a somewhat diflerentconstruction to that of FIG. 1. The interior of the pump chamber isconstituted by a concave recess 111 formed in a block of metal (forexample, aluminium), the diaphragm member 112 extending across thisrecess 111 to seal the pump chamber. A pump actuating rod 116 attachedto the diaphragm member 112 is provided adjacent to the diaphragm member112 with a boss 115 which has a convex surface 115' facing the diaphragmmember 112 and secured thereto on the axis of the rod 116. The convexsurface 115' conforms exactly in curvature with the concave recess 111of the pump chamber.

As in the embodiment of FIG. 1 the pump actuating rod is connected to adouble-acting driving piston 117 mounted in a cylinder 118 and dividingthe interior thereof into two spaces 119, 120. A stop 119' is mounted onthe end wall of the cylinder 118 in the space 119 and a further stop120' is attached centrally to the piston.117 in the space 120. The stops119', 120 limit the travel of the piston 117 on the induction andpumping strokes of the actuating rod 116 respectively.

A cam disc 143 is mounted on the actuating rod 116 between the boss 115and the cylinder 118, and two respective control valves 124, 125 havingrespective actuating plungers 141, 142 are disposed adjacent the rod 116so that the ends of said plungers 141, 142, which are provided with camfollower balls 141, 142', are located in the path of movement of theedge of the cam disc 143 (which is rounded) at the respective positionsoccupied by the disc 143 at opposite ends of the stroke of the drivingpiston 117.

Each control valve 124, 125 is of identical construction, having acylindrical housing 128, 129 in which a valve member 126, 127 isslidably mounted. Each valve member 126, 127 has two spaced apart landswhich make sealing contact with the internal wall of the respectivehousing 128, 129 and which define between them an annular space 130,131. The wall of the housing 128, 129 is provided with two axiallyspaced apart ports connected respectively to a fluid pressure inlet 132,133 and to atmosphere through an outlet 134, 1135, and intermediatethese ports the said wall is provided with a port connected to arespective conduit 136, 137 leading to opposite ends of a cylindricalvalve housing 138. Each valve member 126, 127 is urged by a spring 126',127', in the housing 128, 129 into a position in which the respectiveactuating plunger 141, 142 is extended and the respective pressure inlet132, 1133 is closed, the conduits 136, 137 being connected to therespective outlets 134, 135.

A spool valve 139 is mounted for axial sliding movement in the housing138. The spool valve 139 has four axially spaced apart lands 139' whichmake sealing contact with the internal wall of the housing 138 and whichdefine three axial spaced annular recesses 144, 145, 146 on the spoolvalve. The total length of the spool valve 139 is less than that of thehousing 138 so that the spool valve 139 may occupy either of twosettings in which it is urged against one or the other end wall of thehousing 138 in dependence on the relative fluid pressures in theconduits 136, 137. The axis of the valve housing 138 is disposedhorizontally so that the spool valve 139 remains in the position towhich it is moved by such relative fluid pressures after the pressuresin the conduits 136, 137 have equalised.

Five axially spaced ports are provided in the cylindrical wall of thevalve housing 138; disposed centrally of the housing 138 is a fluidinlet port 140 communicating with a pressure fluid line 140; two ports121', 1-22' are arranged symmetrically on each side of the port 140, andoutwardly of the ports i121, 122' two exhaust outlet ports 134', 135'open to the atmosphere, are provided. The ports 134', 140' and 135' arein permanent communication with the annular recesses 144, 145, 146respectively in 'both settings of the spool valve 139. The two ports121', 122' communicate with respective conduits 121, I122 which in turncommunicate with the first and second spaces 119, of the cylinder 118.

The fluid pressure inlets 132, 133 of the respective control valves 124,are connected in parallel with the pressure fluid line 140 which is inturn connected to a sealed vessel 150 containing solid carbon dioxide asa gas-generating and cooling agent. Coolant comprising water with ananti-freezing agent added thereto is circulated by the pump 110 in aclosed fluid circuit including in series a jacket 152 surrounding thevessel 150 and a fluid-cooled suit 155. The coolant circuit, which isshown in broken lines, is identical to that of FIG. 2 and will not,therefore be described in detail.

The mode of operation of the pumping apparatus of FIG. 3 will beapparent from the foregoing description. Assuming that the ports have aninitial position as illustrated in which the driving piston 117 is atthe extreme left-hand end of the cylinder 118, and against the stop119', then the cam disc 143 will be in engagement with the control valveplunger 141 forcing the valve member 126 inwardly against the action ofthe respective spring 126' so that the exhaust outlet 134 is closed andcarbon dioxide under pressure is supplied to the conduit 146 from theinlet 132 by way of the annular space 130. The other conduit 137 remainsconnected to atmospheric pressure through the space 131 and outlet ofthe other control valve 125, and as a result the spool valve 139 isurged to the left-hand end of its housing 138 into afirst setting asshown in which carbon dioxide under pressure is supplied to the space119 through the line 140, the inlet the annular recess 145, the port 121and the conduit 121, while the space 120 is exhausted to atmospherethrough the conduit 122, the port 122', the recess 146 and the outletport 135'.

The driving piston 117 is therefore moved in the direction of decreasingthe volume of the space 120, that is, to the right in FIG. 3, moving theboss 115 on the actuating rod 116 towards the recess 111 of the pump110'. The pumping stroke of the pump 110 continues, coolant beingexpelled through an outlet non-return valve 114, until the diaphragmmember 112 rests in surface-to-surface 7 contact with the recess 111, atwhich time the stop 120' abuts the respective end wall of the cylinder118, as shown in broken lines.

On commencement of the pumping stroke, the cam disc 143 is moved by theactuating rod 116 out of engagement with the valve plunger 141, so thatthe valve member- 126 is returned by the spring 126 to the position inwhich it connects the conduit 136 to atmospheric pressure through thespace 130 and outlet 134. Both conduits 136, 137 are now at atmosphericpressure, and the resultant axial force on the spool valve 139 istherefore zero. Since, however, the spool valve 139 is disposedhorizontally, it remains in the setting shown until the completion ofthe pumping stroke, as described above.

When the diaphragm member 112 rests on the recess 111 on completion ofthe pumping stroke, the cam disc 143 engages the control valve plunger142 and thereby forces the valve member 127 into the housing 129 untilthe outlet 135 is closed and the conduit 137 put into communication withthe pressure fluid line 140 through the annular space 131 and the inlet133. Carbon dioxide under pressure is now supplied to the left-hand endof the spool valve housing 138, causing the latter to move rapidly tothe right into a second setting in which the pressure fluid line 140communicates with the space 120 through the recess 145 and the conduit122, while the space 119 is exhausted to atmosphere through the conduit121 the space 144 and the outlet port 134'.

The driving piston 117 is now returned to the lefthand end of thecylinder 118, assuming of course that the carbon dioxide pressure issufficiently greater than atmospheric pressure to move the piston 117 inthis direction notwithstanding the smaller area of the piston 117exposed to the pressure in the space 120. The actuator rod 116 is movedto the left, pulling the diaphragm member 112 outwardly, so that coolantis drawn into the pump recess 111 through an inlet non-return valve113'. This induction stroke continues until the piston 117 encountersthe stop 119, when the cam disc 143 will again engage and depress thevalve plunger 141 to effect a changeover of the setting of the spoolvalve 139, as described above.

The pump 110 is therefore operated continuously as long as the carbondioxide pressure is maintained.

The pumping apparatus shown in FIG. 4 comprises a cylindrical housing159 with a central, inwardly projecting annular flange 160. Contained inthe housing, and disposed co-axially therewith, is a movable actuatormember comprising a central rod 161 carrying at opposite ends thereofdisc elements 162 and 163. The disc elements 162 and 163 are carriedcentrally in respective flexible diaphragms 164 and 165 whose outeredges are secured and sealed to the housing 159. The disc element 162has a downwardly projecting annular edge flange 166 which carries arubber sealing ring 167, and the disc element 163 has a correspondingupwardly projecting annular edge flange 168 carrying a rubber sealingring 169.

When the'actuator member is in its uppermost position (shown in FIG. 4)the sealing ring 169 abuts the lower face of the flange 160 and sealsoff an exhaust port 170 provided therein, a further exhaust port 171 inthe upper face of the flange 160 being open. When the actuator member isin its lowermost position the sealing ring 167 abuts the upper face ofthe flange 160 and seals off the port 171, the port 170 then being open.The purpose of the ports 170 and 171 is explained later.

Secured to the housing 159 are upper and lower end plates 172 and 173respectively. As can be seen from FIG. 4, the disc elements 162 and 163and their associated diaphragms 164 and 165 eflectively divide theinterior of the housing 159 into three chambers sealed from each other,namely an upper chamber between the end plate 172 and the diaphragm 164,a central chamber between 8 the diaphragms 164 and 165, and a lowerchamber between the diaphragm and the end plate 173.

Coolant fluid to be pumped can enter the upper chamber through an inlet174 having an associated non-return valve 175, and can be pumped fromthe upper chamber through an outlet 176 having an associated non-returnvalve 177. Gas under pressure can enter the lower chamber through aninlet 178. The central chamber with which the ports and 171 communicate,has a vent hole 179 leading to atmosphere.

A helical spring 180, disposed between the flange 160 and the discelement 163, urges the actuator member 161, 162, 163 downwardly.

In operation, the actuator member is urged downwardly in an inductionstroke under the action of the spring 180, thereby increasing the volumeof the upper chamber and drawing fluid thereinto through the inlet 174.Downward movement of the actuator member ceases when the sealing ring167 abuts the flange 160. Gas under pressure is then introduced into thelower chamber through the inlet 178 to move the actuator member upwardly(against the action of the spring 180) in a pumping stroke. Such upwardmovement decreases the volume of the upper chamber, causing fluidtherein to be pumped through the outlet 176, and continues until thesealing ring 169 abuts the flange 160. The actuator member then movesdownwardly in a further induction stroke, the inlet 178 to the lowerchamber then acting as an exhaust outlet.

The supply of gas under pressure to the lower chamber is controlled by aspool valve 181 mounted for axial sliding movement in a housing 182. Thevalve 181 has three axially spaced apart lands 183 which make sealingcontact with the internal wall of the housing 182 and which define twoaxially spaced annular recesses 184 and 185 on the spool valve. Thevalve 181 may occupy either of two settings in which it abuts one or theother of the housing end walls. The housing 182 has end ports 187 and188 at which gas pressure can be applied to eifect respective changes insetting of the 'valve 181.

Three axially spaced ports are provided in the cylin- 'drical wall ofthe housing 182; disposed towards one end of the housing 182 is a gasinlet port 189 communicating with a gas pressure line 190; a port 191 isdisposed substantially centrally of the housing and communicates via aline 193 with the pump chamber inlet 178; and an exhaust outlet port 194is disposed towards the other end of the housing. When the valve 181 isin the setting shown in FIG. 4, the annular recess 185 provides acommunication between the inlet port 189 and the port 191. When thevalve 181 is in its other setting, i.e. has been moved to the right asviewed in FIG. 4, the annular recess 184 provides a communicationbetween the ports 191 and 194.

The gas pressure line 190 forms one arm of a cross junction, theopposite arm of which comprises a pipe 196 communicating with a sourceof gas pressure indicated as 197. A further arm of the junction isprovided by a pipe 198, having a restrictor 199, and which communicateswith a duct 200 in the pump housing 159 leading to the exhaust port 170.The pipe 198 has a control outlet 201 forming a T junction andcommunicating with the end port 187 of the spool valve housing 182. Thefourth arm of the cross junction is provided by a pipe 202, having arestrictor 203, and communicating with a duct 204 in the pump housing159 leading to the port 171. The pipe 202 has a control outlet 205forming a T junction and communicating with the end port 188 of thespool valve housing 182.

At the end of a pumping stroke the sealing ring 169 blocks the port 170,as shown in FIG. 4. Gas pressure from the pipe 198 is therefore appliedat the control outlet 201 and hence at the end port 187 of the spoolvalve housing. Since the port 171 is at this time open gas can flow fromthe pipe 202 through the duct 204 and the port 171 into the pumpscentral chamber, and therefrom through the vent hole 179, so that nosubstantial pressure is applied at the end port 188 of the spool valvehousing. The greater pressure at the end port 187 therefore etfects achange of setting of the spool valve 181 by moving the latter to theright as viewed in FIG. 4. After such change of setting, the annularrecess 184 provides a communication between the port 191 and the exhaustport 194. The actuator member is moved downwardly under the action ofthe spring 180 in an induction stroke, and during such movement, gasfrom the lower chamber of the pump flows to exhaust through the inlet178, the port 191 and the exhaust port 194.

At the end of the induction stroke the sealing ring 167 blocks the port171, the port 170 then being open. Gas pressure from the pipe 202 istherefore applied at the control outlet 205 and hence at the end port188 of the spool valve housing. Since the port 170 is open gas can flowfrom the pipe 198 through the duct 200 and the port 170 into the pumpscentral chamber, and therefrom through the vent hole 179, so that nosubstantial'pressure is applied at the end port 187 of the spool valvehousing. The greater pressure at the end port 188 therefore effects achange of setting of the spool valve 181 by moving the latter to theleft as viewed in (and back to thei'position shown in) FIG. 4. Aftersuch change of settingfi the annular recess 185 provides a communicationbetween the inlet port 189 and the port 191. Gas flows from the pressureline 190 to the port 191 and thence through the line 193 to the pumpinlet 178, so that the actuator member moves upwardly in a pumpingstroke.

The values of the restrictors 199 and 203 in the pipes 198 and 202respectively are chosen to maintain a sufficient pressure of gas flowthrough the pressure line 190 to effect the required pumping operationnotwithstanding flow through the pipes 198 and 202. It will be seen thatduring actual movement of the actuator member in a pumping stroke bothof the ports 170 and 171 are open; the restrictors 199 and 203 presentan impedance to the flow through these pipes from the pipe 196,andthereby to maintain a suflicient pressure in the line 190 to effectthe pumping stroke.

The source of gas pressure, indicated at 197 in FIG. 4, is provided bysolid carbon dioxide which absorbs heat from the coolant fluid pumpedround a circuit including channels in a protective suit, in essentiallythe same manner as previously described in relation to FIGS. 2 and 3.

It should be noted that the combined pumping and cooling systemsdescribed above are to some extent selfadjusting. Thus if thetemperature of the coolant should increase, due to an increase in theheat to which the associated protective suit is exposed, the rate ofsublimation of carbon dioxide (or other cooling agent) in the sealedvessel which acts as the source of fluid pressure for the pumpingapparatus will increase. Consequently* the gas pressure during thepumping apparatus will increase, thereby increasing the speed ofoperation of the pumping apparatus and, therefore, its pumping rate. Theresulting increased rate of circulation of coolant will ISLllt in alowering of the coolant temperature. The pumping rate will eventuallyadjust to a new level such thaflthe temperature difference between thecoolant at the inlet and that at the outlet of the protective suit ismaintained substantially constant.

In a modified form of apparatus according to the invention, thediaphragm pump 10, 110 in the embodiments of FIGS. 1 and 3 could bereplaced by a positive displace ment pump of the reciprocating pistontype; similarly, a diaphragm member could be used in place of thedriving piston 17, 117.

We claim:

1. A portable, self-contained pumping and cooling system for anappliance comprising a coolant flow passage adapted to form part of acoOling circuit extending through the appliance, a scalable vesselarranged in heat-exchange relationship with the coolant flow passagewhich is adapted to form part of a coolant circuit, said vessel beingadapted to contain an evaporating refrigerant which releases pressurefluid upon absorption of heat, a fluid pressure-actuated reciprocatingpump connected in the coolant circuit, said pump comprising a pumpchamber having an inlet and an outlet respectively fitted with inlet andoutlet nonreturn valves, a diaphragm member forming a movable wall ofthe pump chamber, which member has its edge secured to the peripheralwall of the pump chamber and is adapted to flex so as to change theeffective volume of the pump chamber to draw fluid into the pump chamberthrough said inlet during'lthe induction stroke of the pump and todischarge the fluid through said outlet during the pumping stroke, andan actuator member rigidly connected to said diaphragm member and housedin a second chamber and having a control connection to the vessel forsupplying pressure fluid to move the actuator member to effect at leastsaid pumping stroke of the pump, valve means second chamber and havingtwo settings corresponding to v the induction and pumping strokes of thepump, and changeover means effective to change the setting of the valvemeans cylically SQ-that the moving members of the pump elfect continuousr' eciprocation.

2. A system according to claim 1, wherein the valve means has two fluidoutlets to the second chamber and is operable to supply pressure fluidfrom the scalable vessel to the two outlets in turn thereby causing theactuator member to reciprocate and effecting the induction and pumpingstrokes of the pump.

3. A system according to claim 1, wherein the changeover means isconnected to the rigid connection means between the moving members ofthe pump and is effective automatically when the'imoving members of thepump are at the end of a stroke to change the setting of the valve meansso that the pump commences the next stroke.

4. A system according to claim 1, wherein a change of setting of thevalve means is effected by the application of fluid pressure controlledby the changeover means, the changeover means being effective to providea communication between said vessel and a fluid inlet associated withsaid valve means, at which inlet fluid pressure can be applied to effecta change'fof setting of the valve means.

5. A system according to claim 4, wherein the valve means comprise aspool valve movable axially in a housing, the changeover means beingeffective to provide selectively a communication between said vessel anda fluid inlet at one end of said housing, and between said vessel and afluid inlet at the other end of said housing, a change of setting of thevalve means being effected by application of fluid pressure at the fluidinlet at the appropriate end of said housing to move the spool valveaxially.

6. A system according to claim 1, wherein spring means are provided tomove the actuator member to effect the induction stroke of the pump.

7. A system according to claim 4, wherein the changeover means comprisesealing means mounted for movement with the moving members of the pumpand arranged to block an exhaust port when the moving members of thepump are at the end of a stroke, a duct providing communication betweensaid exhaust port and said vessel, and having a control outletcommunicating with said duct at which fluid pressure can be applied toeffect a change of setting of the valve means, whereby when said exhaustport is blocked by the sealing means fluid pressure is applied at saidcontrol outlet to cause a change in setting of the valve means.

8. A system according to claim 7, including a first duct having anexhaust outlet and communicating with a control outlet at which fluidpressure can be applied to change the valve means from a first settingto a second setting, and a second duct having an exhaust outlet andcommunicating with a control outlet at which fluid pressure can beapplied to change the valve means from said second setting to said firstsetting, said first and second ducts communicating with said vessel, andwherein the pump has associated therewith respective sealing meanseffective to block the exhaust outlets of said first, and second ductswhen the pump is respectively at the end of a pumping stroke and aninduction stroke, so that fluid pressure is applied to the first andsecond control outlets alternately.

9. A system according to claim 1, wherein said scalable vessel comprisesa container for the evaporating refrigerant enclosed in a jacket whichdefines with the container said coolant flow passage.

10. A system according to claim 1, wherein the appliance is a protectivesuit and wherein said coolant flow,

passage that is in heat exchange relationship with the 15 vessel, isconnected to coolant flow passages in the protective suit.

References Cited UNITED STATES PATENTS 2,380,537 7/1945 McMechon 623842,383,486 8/1945 Isenberg 62384 2,760,345 8/1956 Woods 62-384 3,112,79212/1963 Coleman 62259 10 WILLIAM J. WYE, Primary Examiner US. Cl. X.R.62384

